| Volumes Volume 1 Contents of Current Session |
www.adv-radio-sci.net/1/37/2003/
© Author(s) 2003. This work is licensed
under a Creative Commons License.
Broadband suppression of phase-noise with cascaded phase-locked-loops for the generation of frequency ramps
Institut für Hochfrequenztechnik, Ruhr-Universität Bochum, Germany
Abstract. The generation of analogue frequency ramps with non-fractional phase-locked-loops (PLL) is a cost effective way of linearising varactor controlled oscillators (VCO). In case that the VCO shows a high phase-noise level, a single non-fractional PLL is not able to suppress the phase-noise of the VCO sufficiently. The reason for this is the limited loopbandwidth of the PLL. In the field of precise measurements a high phase-noise level is mostly not tolerable. Examples of VCO-types with an extremely high phase noise level are integrated millimetre wave oscillators based on GaAs-HEMT technology. Both, a low quality factor of the resonator and a high flicker-noise corner frequency of the transistors are the main reason for the poor phase-noise behaviour. On the other hand this oscillator type allows a cost effective implementation of a millimetre-wave VCO. Therefore, a cascaded two-loop structure is presented that is able to linearise a VCO and additionally to reduce its phase-noise significantly.
Full Article in PDF (PDF, 1250 KB)
Citation: Musch, T.: Broadband suppression of phase-noise with cascaded phase-locked-loops for the generation of frequency ramps, Adv. Radio Sci., 1, 37-41, 2003. Bibtex EndNote Reference Manager
